AusBonsai

It seems quite hard to find any nurseries or shops that sell and ship trees as online orders. I understand that shipping Bonsai wouldn't be easy but the US in particular seems to have a huge number that ship quite expensive trees. I also understand that certain states have restrictions which isn't a great motivator to offer shipping.

The only ones I've managed to find ship cheap ficus/figs only.

Are there any that do ship within Australia with somewhat of a wide tree selection?

You cant ship anything into Tasmania or Western Australia.

There are plenty of places that ship.

I find that Neil from shibui nursery is the best.

http://shibuibonsai.com.au/.

He regularly posts on this site and has a large range of trees. His postage is always fair.

Good luck

I have only had experience shipping plants with Shibui, and young stock at that not large trees, but can say that he was excellent to work with. Myself and another member purchased some trees a day or two apart, so there was some back and forth working out getting postage to one address etc. but all was easily enough handled and the plants arrived well packaged and safely in very quick time.

As mentioned there are strict laws about shipping into WA and TAS, but there are none about shipping out as far as i'm aware. Since you are in Sydney those laws shouldn't factor.